Transaction

[Error Code: 1101] cadence runtime error Execution failed:
error: underflow
  --> 756f8ce532c39ec5f47ecc39ab925b200e5ba2eaafb7cea52c1a6e7b09bf102b:16:8
   |
16 |         let total: UFix64 = SwapConfig.ScaledUInt256ToUFix64(res) - 0.2
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^